Effort To Save Sequoias In Yosemite

Inmate firefighters walk along Highway 120 as firefighters continue to battle the Rim Fire near Yosemite National Park, Calif., on Sunday, Aug. 25, 2013. Fire crews are clearing brush and setting sprinklers to protect two groves of giant sequoias as a massive week-old wildfire rages along the remote northwest edge of Yosemite National Park. (Jae C. Hong/AP)

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Originally published on August 27, 2013 3:02 pm

The giant Rim Fire raging near Yosemite National Park is threatening two groves of giant sequoias: the Tuolumne Grove and the Merced Grove.

The redwoods have some natural defenses against wildfires, but firefighters are clearing brush near the groves and setting up sprinkler systems to provide the ancient trees with extra help if the fire does spread to the groves.

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It's HERE AND NOW. After 10 days, progress has been made on the Yosemite Rim Fire. As of this morning, fire officials say the blaze has been 20 percent contained, though it has already burned some 160,000 acres. Nearly 3,700 firefighters have been involved in battling the fire, and there is still concern about possible effects on San Francisco's water supply because the main reservoir for the city is very close to the fire. There is also concern about the proximity of the fire to two grooves of giant sequoia trees.

And measures have already been taken to protect one of the park's signature attractions. Tom Medema joins us from the incident command post near Groveland, California. And Tom, how close have the fires gotten to the sequoias?

TOM MEDEMA: Right now the fires are still five or six miles from the giant sequoias. They're burning fairly slowly in that direction because it's against the prevailing winds, but they still are making some progress in that area.

HOBSON: You've been out there in the sequoia grooves. What is it like there right now?

MEDEMA: Well, there's — we've got sprinklers running down there, moistening the fuels around the perimeter of the groves. We have done some fuels reduction in that area, taking away opportunities for fuels to burn up into the higher reaches of the trees. We've got a historic structure in the Merced groove that we wrapped in a fireproof material to help preserve that structure. So there's been a number of steps in both groves to protect those trees and those resources.

HOBSON: And we should say that sequoias have some natural defenses against fire. Tell us about those.

MEDEMA: Yeah, yeah. Sequoia is one of those species that thrives in a normal fire environment. They're a sun-loving species. And so when a ground fire comes through at a natural burn, it opens up the cones and releases the seeds. It creates sunlight for those seedlings to germinate and to grow. The mature sequoias have an incredibly thick bark that's resistant to fires. So again, those low-intensity ground burns are very healthy for the sequoia environment. It's still those hot, high-intensity crown fires that no stand can really afford to have.

HOBSON: Even that thick bark would not be defense enough against the fire that we're looking at right now?

MEDEMA: Well, it's primarily that the fire can get up into the tops and then to the needles and leaves up in the tops of the trees. And so that greenery up at the top can actually catch fire, whereas a normal fire would burn at the base of the tree and be impervious because of the bark. And so that would be the same, but it's actually the crowning nature of this fire that carries the fire into the grove way up off the ground. That's the real threat.

HOBSON: At this point, are there any tourists and campers there left looking at the sequoias?

MEDEMA: Not looking at those sequoias. The Mariposa Grove of giant sequoias, which is our largest grove, is still very much open and active, lots of visitors there. Most of our campgrounds are still full. And Yosemite Valley is still full, and all of its attractions are accessible. So - but those two smaller grooves right now are closed to the public.

HOBSON: Tom Medema is a spokesperson for Yosemite National Park, talking with us about some groves of sequoias that are somewhat close to the Rim Fire, although so far so good. Tom, best of luck.